Worm-gearing.



UNITED STATES PATENT OFFICE.

NORMAN C. BASSETT, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRICCOMPANY, OF NEW YORK.

WORM-GEARING.

SPECIFICATION forming part of Letters Patent NO. 679,356, dated July 30,1901;

Application filed October 26, 1900. Serial No. 34,492- (No model.)

T at whom it may concern:

Be it known that I, NORMAN C. BASSETT, a

citizen of the United States, residing at Lynn,

county of Essex, State of Massachusetts, have invented certain new anduseful Improve ments'in Worm-Gearing, (Case No.,1,468,)ofwhich-.theifollowing is a specification.

Thistinwention relates to improvements in worm-gearing for transmittingpower from motors.

A considerable part of the inefficiency of worm gearing is due to thegreat friction on the bearings resulting fromend thrust of theworm-shaft. It is the design of my invention to promote the transmittingefficiency of the gearing by avoiding this end thrust, and I accomplishthe result by giving the wormshaft a bias or thrust in a directionopposite to that imposedby the load and sufficient when the load isnormal to counterbalance.

the end thrust. Thus the worm-shaft engages only the worm-wheel, and thefriction due to lateral thrust is avoided. This bias may be effected ina Variety of ways, depend- 2 5 ing on the type of motor and the positionof the shaft; but I prefer to effect it by mounting the worm-shaftvertically and loading it so that it will counterbalance the normalworking load.

0 The invention is of particular advantage in connection withworm-gearing driven by electric motors, in which case the armature ofthe motor may be mounted on the wormshaft and by reason of its weightact as a 3 5 counterbalance to the normal load; In addition to this thedirection of motion transmitted is such that the efiort of the load isto raise the worm-shaft and lift it out of mechanical contact with itslower bearing and hold it floating, as it were, while the worm transmitsmotion to the wheel it engages. In such a case the field-magnet of themotor acts in the capacity of a frictionless spring or cushion, whichassists the weight of the parts 5 in balancing the load, since anytendency of the load to raise the Worm-shaft tends to deflect thearmature into an unsymmetrical position with relation to itsfield-magnet, and the latter resists such a tendency.

My invention therefore comprises wormgearing in which the worm-shaft isgiven a bias to counterbalance the normal load in or der to prevent thelosses due to end thrnst..

It comprises also a system of gearing in which the worm -shaft ismounted vertically and given a bias by weighting or otherwise tocounterbalance the load; It comprises also the combination ofan-electric motor the armature of which is mounted on a verticalworm-shaft, and gearing so related to the load that the latter will tendto lift the shaft. It comprises also details of construction, thenovelty of which will be specifically pointed out hereinafter and whichwill be definitely indicated in the claims appended to thisspecification.

In the accompanying drawings, which illustrate one form of my invention,Figure 1 is a sectional view of a system of worm-gearing driven by abipolar electric motor, as adapted for use in operatingli'notype-machines. Fig.

2 is an elevation on a plane at right angles to that indicated in Fig 1.

1 represents a Worm -shaft, the worm 2 of which engages a Worm-wheel 3.On the shaft 7 5 is mounted an armature 1 of an electric motor, of which5 .is the commutator and 6 the field-magnet. The motoris shown insection, one coil being indicated at 7 and the tip of the rearpole-piece being seen at 8. The gearing and motor are surrounded byacast-metal casing adapted to be separated at suitable points, asindicated in the drawings, for assembly and withdrawal of the parts whennecessary. The upper end of the Worm-shaft turns in a bearing in thelining of which are placed pads of felt or other absorbent of oil, asindicated at 9,and over the end of the shaft is laid a disk of felt 10,above which is supported an oil-pot 11. ing is placed a thimble 12, onthe shaft flanged at the top, as indicated in Fig. 1, to deflect the oilfed from the oil-pot 11 to a hole drilled in the casting of themotor-casing, as seen at 13. A hole 14, bored in the bottom of 5 thischannel close to the side of the casing, permits the oil to flow downover the inside into a gutter 15, the end wall of which constitutes ascraper to remove excess of oil from the worm-wheel. This gutter leadsthe oil to an intermediate bearing 16 of the worm-shaft, through whichit passes and discharges upon WVithin the motor-cas- 0 fastened to theshaft of the machine.

the worm. The casing for the gear-wheel 3 contains a well 17, into whichdirt may settle. The lower part of the worm-wheel casing is madeliquid-tight, so that the oil-level may be raised to a point where itwill partially submerge the worm-wheel.

In the operation of the apparatus the wheel carries the oil with it tothe scraper, where the excess is removed, and thus sufficient oil is fedto the intermediate bearing 16 and worm to permit an easy operation. Tothe lower end of the worm-shaft is connected a piston 18, provided witha number of horizontal grooves on its periphery, which makes an easy fitwith the lining 19 for the bottom bearing. The shaft rests, when themachine is not running, on a hardened-steel plate 20, fixed in ascrew-cup 21, inclosing the end of the shaft. The cup and piston form adashpot, which resists sudden motions up or down of the worm-shaft,thereby preventing blows due to end thrust on a sudden change of load.

22 represents a combined clutch and pulley the outer rim of which servesas a pulley and the inner face acts on a clutch member This forms nopart of my invention, but is of advantage in operatinglinotype-machines, for which my invention is well adapted.

The weight of the armature and worm-shaft maybe so designed as to justcounterbalance the lifting effect of a normal load on the drivenmachine. Any excess of load tending to raise the shaft in the case of anelectric motor-driven outfit would lift the armature relatively to itsfield of force, and such an effort would be strongly resisted by themagnetic pull between the armature-core and the field-magnet. Thus whenthe gearing is in operation the worm floats, as it were, in itsbearings, and the efficiency of power trans mission between the motorand the work is greatly increased.

The oil fed from the pot 11, after lubricating the top bearing, dripsfrom the flange of the thimble 12 and passes through the hole 14: overthe inner vertical wall of the motorcasing to the gutter formed in thescraper 15, then lubricates the intermediate bearing 16, and falls uponthe worm-wheel. The excess of oil from the worm-wheel drops into a cup23, formed in the upper part of the bottom hearing, which will be keptfull when the apparatus is in action. From this it leaks into thedash-pot, and the latter is kept filled. The thimble 12 may have apushing fit on y the shaft, so that it may be removed in order to permitthe top of the motor-casing to be taken off.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent of the United States, is-

1. The combination of a worm-wheel and a worm-shaft adapted to shiftendwise under load, with means for giving the worm-shaft a bias tocounterbalance the normal load driven by the wheel, whereby the frictionof end thrust is obviated.

2. The combination of a worm-wheel and a vertically-mounted worm-shaftweighted to counterbalance the normal load driven by the wheel.

3. The combination of a wormwheel, a wormsl1aft, means for giving a biasto counterbalance its end thrust, and a dash pot to oppose suddenchanges of movement of the shaft.

4:. The col'nbination of a worm wheel, a worm-shaft and an electricmotor driving the same, the armature of the motorbeing mounted on theshaft and fixed thereon to hold the shaft against end thrust whensymmetrical in its field of force.

5. The combination of a wormwvheel, a vertical worm-shaft, an electricmotor driving the same, the armature of the motor being mounted on theshaft, the parts being so adjusted that when the armature is symmetricalwith relation to its field, the shaft floats in its bearings.

6. The combination of a worm-wheel, a Vertical worm-shaft, an oil-feedat the top of the shaft, and guides for leading the oil from the topbearing to the bottom bearing over the Working face of the worm.

In witness whereof I have hereunto set my hand this 24th day of October,1000.

NORMAN O. BASSETT.

Witnesses:

DUGALD MOKILLOP, JOHN J. WALKER.

